My friends at AZP Installs in Kenilworth do my differential service, like clockwork. I’m currently doing my 90,000(ish) service, and decided to take some pics. Not just did the magnet plug look great, with nothing that mattered on it, but each and every geartooth is still sharp and super shiny, as if they were new and just installed. Heck, the edges of the teeth are still factory sharp.
Break in and proper maintenance works really well.
On the other hand, sadly, some people have towed in their first few miles. Not a good plan, as they found out sadly. These little beasties survive lots of abuse if broken in properly and properly maintained.